土木工程專業(yè)畢業(yè)設(shè)計(jì)外文翻譯---地下空間的利用

1、<p><b>　　地下空間的利用</b></p><p>　　全球城市化進(jìn)程的加快將會(huì)對(duì)人類將來的生存方式產(chǎn)生重大影響。隨著全球人口的增長(zhǎng)以及更多國家要求提高生活水平，世界必須提供更多食物，能源以及礦物資源來維持此增長(zhǎng)趨勢(shì)。解決這一難題的辦法有三大渠道復(fù)合而成：農(nóng)業(yè)用地的保護(hù)從而得到更深入的利用；日益增長(zhǎng)的全球城市人口；對(duì)保護(hù)和改善環(huán)境日益增長(zhǎng)的關(guān)注，特別是關(guān)于全球氣候變暖以及人

2、口增長(zhǎng)帶來的影響。地下空間的利用，作為本章要描述的內(nèi)容，將提供針對(duì)這些趨勢(shì)的解決辦法。</p><p>　　通過將特殊器材設(shè)備置于地下，城市地表可被更有效地利用，這樣就可釋放出空間供農(nóng)業(yè)和娛樂使用。類似的，在陡峭的山坡上使用階地掩土住宅會(huì)有助于在多山地區(qū)保護(hù)寶貴的可耕平地。利用地下空間也可以提高人們?cè)谌丝诟呙芗サ木幼∈孢m度，改善生活質(zhì)量。</p><p>　　一城市或當(dāng)?shù)厮疁?zhǔn)，地下設(shè)施的

3、利用正日益滿足當(dāng)今社會(huì)對(duì)于改善環(huán)境的需求。例如不論城市還是農(nóng)村都需要提高運(yùn)輸，實(shí)用以及娛樂服務(wù)。世界上許多城市的交通堵塞問題已經(jīng)處在滿足人類基本生存需求的臨界點(diǎn)上，并且在不破壞地表環(huán)境的基礎(chǔ)上不增加新設(shè)施或是不重新規(guī)劃現(xiàn)有土地及周邊地帶上的建筑的基礎(chǔ)上想要解決這一難題是十分困難的。</p><p>　　以世界上許多國家的國家水平，全球化的趨勢(shì)導(dǎo)致對(duì)煤炭，石油，天然氣的開采已達(dá)到更深的地層以下，觸及更難以讓人接受或

4、是更敏感的區(qū)域。這些趨勢(shì)同樣導(dǎo)致針對(duì)能源繁衍存貯系統(tǒng)以及用于處理危險(xiǎn)廢料（包括化學(xué)，生物以及放射性廢料）的國家設(shè)施設(shè)計(jì)的改善和提高，同樣也改善了國家高速運(yùn)輸體系。所有這些發(fā)展均涉及地下工程。</p><p><b>　　用地壓力</b></p><p>　　將設(shè)施置于地下是緩解由于世界人口增長(zhǎng)所帶來的城市化問題的一種有希望的辦法。雖然世界平均人口密度并不大，但人口分布

5、卻極不均勻。世界人口密度圖顯示世界上大部分地方根本不適合居住。這些大方大部分是沙漠山區(qū)，或是極度嚴(yán)寒地帶等人類不易居住區(qū)。</p><p>　　以中國為例，平均人口密度大概是每平方公里100人，但是10億多的絕大部分人口居住在少于20%的國土上。這是那些可以提供糧食產(chǎn)品的肥沃土地。然而，由于人口增長(zhǎng)和城市化，這些土地同樣要被用于創(chuàng)建更廣闊的運(yùn)輸系統(tǒng)，被用于工商業(yè)的發(fā)展，以及日益增長(zhǎng)的住房需求。隨著人口和經(jīng)濟(jì)的增長(zhǎng)

6、，農(nóng)業(yè)用地減少，向城市人口運(yùn)送食物和原材料的問題日益增長(zhǎng)。據(jù)估計(jì)，到2000年，世界人口的70%將居住在城市。</p><p>　　同樣的問題在日本也很明顯，大約80%的土地是山區(qū)，90%的人口居住在海邊平原經(jīng)濟(jì)發(fā)展集中在幾個(gè)相關(guān)的經(jīng)濟(jì)中心。平原通常是最肥沃的土地，從歷史上看也是人類的定居地。其他附加于人口密度的因素包括：傳統(tǒng)低層的建筑模式，而且日本法律規(guī)定必須建造靠近陽光的堅(jiān)固的維護(hù)設(shè)施。同樣，為了保護(hù)家庭糧食

7、生產(chǎn)能力，日本政府保護(hù)農(nóng)業(yè)用地。這些歷史，政策因素導(dǎo)致大量商業(yè)，個(gè)人向經(jīng)濟(jì)中心移民造成了巨大的土地使用壓力。結(jié)果是市中心土地價(jià)格驚人昂貴（高達(dá)50萬美圓/平米）并且很難為人們提供住房，交通，設(shè)施服務(wù)。普通公司雇員無法承擔(dān)住在他們工作的市中心附近而不得不搭乘公汽單程花1.2個(gè)小時(shí)從他們負(fù)擔(dān)的起的住處到公司。為了為日益擴(kuò)大的大城市區(qū)域提供服務(wù)，市政當(dāng)局必須升級(jí)道路并且興建新的交通線和設(shè)施。東京市中心的土地價(jià)格如此昂貴以至于用于購買土地的花費(fèi)

8、可能會(huì)占到工程總花費(fèi)的95%。</p><p>　　土地使用壓力和由于高土地使用價(jià)格帶來的相關(guān)經(jīng)濟(jì)影響使得對(duì)地下空間的潛在利用的研究變得相當(dāng)有趣。當(dāng)?shù)乇硗恋匾驯焕么M，地下空間將變成可開發(fā)的區(qū)域之一。這為不需深度破壞地表環(huán)境而附加需要設(shè)備提供了一種可能。雖然沒有高額地價(jià)，但是建造地下設(shè)施的高額花費(fèi)將是地下空間利用的一大攔路虎。因?yàn)榈叵略O(shè)施不具有經(jīng)濟(jì)競(jìng)爭(zhēng)力，因此在考慮建造前必須在美學(xué)，環(huán)境或者是社會(huì)效應(yīng)方面給予綜

9、合評(píng)估，除非是一些有特殊標(biāo)志性意義的設(shè)施否則將會(huì)造成現(xiàn)階段國家無法承擔(dān)或是很勉強(qiáng)承擔(dān)的奢侈浪費(fèi)。</p><p><b>　　地下空間規(guī)劃</b></p><p>　　對(duì)地下空間利用的有效規(guī)劃是發(fā)展地下設(shè)施的前奏。這個(gè)計(jì)劃必須是為長(zhǎng)遠(yuǎn)考慮的，并根據(jù)人們理想的工作和居住環(huán)境重構(gòu)城市建筑格局。如果地下空間開發(fā)可以提供最具價(jià)值的長(zhǎng)期效益，那么對(duì)這些資源的有效計(jì)劃就應(yīng)得以實(shí)施

10、。不幸的是，在世界范圍內(nèi)，靠公眾權(quán)力來開發(fā)近地表空間已經(jīng)太遲了。紊亂的設(shè)施網(wǎng)絡(luò)司空見慣歸咎于缺乏協(xié)調(diào)以及使用設(shè)施的歷史性變革以及交通系統(tǒng)的發(fā)展。</p><p>　　地下空間具有如此特征導(dǎo)致要做一個(gè)好的規(guī)則需要特別注意一些問題</p><p>　　1.一旦開始地下開挖，土地將被永久改變。地下建筑不象表面建筑那樣容易拆掉。</p><p>　　2.開挖一片地下空間需要

11、一大片土地作為開挖加固區(qū)。</p><p>　　3.土地的地理構(gòu)成極大地影響了地下設(shè)施的種類，形式以及開銷。但現(xiàn)有關(guān)于地表建筑的知識(shí)僅有很有限的內(nèi)容與此相關(guān)，因此需要查閱鉆探資料和以前的記錄。</p><p>　　4.大型地下工程需要大量調(diào)查，涉及更大的建造問題，工期拖延以及預(yù)算超支等風(fēng)險(xiǎn)。</p><p>　　5.傳統(tǒng)規(guī)則技術(shù)主要側(cè)重于對(duì)于城市地形區(qū)域的二維描述。

12、這基本上僅適合地表及上部結(jié)構(gòu)但并不適合建造在處于復(fù)雜三維地理環(huán)境中的地下結(jié)構(gòu)。用同一種模式來描述這種三維信息并立刻反映到規(guī)則評(píng)估中是件非常困難的事</p><p>　　例如，在東京，第一條地鐵（Ginza線）是在現(xiàn)存地表層設(shè)施下作為一個(gè)影子工程線路（10m深）建成的。隨著填加更多的地鐵線，在更深土層中才會(huì)發(fā)現(xiàn)比較規(guī)整的區(qū)域。在東京，新的KeiyoJR線深達(dá)40m。一條從Marunouchi到Shinjuku的高速

13、干線已被設(shè)計(jì)到50m深。作為比較在倫敦最深的設(shè)施大約70m深，其主要復(fù)雜部分以及排水設(shè)施至少超過25m綜合日益增長(zhǎng)的需要，有一個(gè)事實(shí)就是這類新型運(yùn)輸服務(wù)（例如日本的新干線子彈頭列車或是法國的TGV）通常需要大量交叉隧道，筆直的隊(duì)列以及平坦性。如果地下空間不是此類用途，那么城市下面將會(huì)產(chǎn)生非常無效率的布局。</p><p><b>　　環(huán)境利益</b></p><p>

14、　　另一個(gè)利用地下空間的主要策略是全球日益增長(zhǎng)的對(duì)環(huán)境問題的關(guān)注，并導(dǎo)致人們重新考慮城市的將來和工業(yè)的發(fā)展。在關(guān)注維持生態(tài)平衡和環(huán)境惡化以及全球有限的自然資源要考慮以下幾個(gè)問題：</p><p>　　1.日益增長(zhǎng)的能源消費(fèi)量相對(duì)于滿足將來需求的有限礦物燃料的貯備</p><p>　　2.由于燃燒礦物燃料對(duì)全球氣候帶來的影響</p><p>　　3.工業(yè)副產(chǎn)品對(duì)環(huán)境的

15、污染</p><p>　　4.對(duì)于工業(yè)生產(chǎn)及軍事演習(xí)產(chǎn)生的危險(xiǎn)廢物的安全處置</p><p>　　在提高經(jīng)濟(jì)增長(zhǎng)保持工業(yè)模式的同時(shí)保護(hù)環(huán)境，延長(zhǎng)地球上資源的壽命即使不是一個(gè)不可能的問題也是一個(gè)很復(fù)雜的問題。無論如何，高生活標(biāo)準(zhǔn)和高國內(nèi)生產(chǎn)總值（GDP）不需要和資源的消耗和環(huán)境的惡化程度成比例。</p><p>　　地下空間的利用能從幾種途徑解決環(huán)境/資源的窘境。地下

16、設(shè)施以其自身特點(diǎn)成為一種典型的儲(chǔ)能設(shè)施。更重要的是，通過地下空間的利用，城市人口密度會(huì)提高但對(duì)環(huán)境的影響會(huì)減少。相對(duì)于保護(hù)綠地及耕地等的明顯好處，附加于此的好處是------有充分證據(jù)顯示高城市密度可以減少礦物燃料的消耗。</p><p><b>　　將來地下空間的發(fā)展</b></p><p>　　雖然在全世界范圍內(nèi)現(xiàn)有的地下設(shè)施為將來地下空間的發(fā)展提供了一些范例，但

17、他們都在尺寸上，用途上或者對(duì)于城市整體環(huán)境缺乏考慮。作為更佳細(xì)致規(guī)劃和研究的補(bǔ)充，未來的規(guī)劃者和設(shè)計(jì)者已提出對(duì)大范圍地下結(jié)構(gòu)甚至從整個(gè)城市的角度綜合考核，將是非常有用的。</p><p>　　90年代地理——一個(gè)1990年4月在日本舉行的研討博覽會(huì)，主要是一個(gè)關(guān)于日本地下工業(yè)情況的論壇。一大堆關(guān)于地下的概念展示出來——從典型的運(yùn)輸使用設(shè)施到展望中的用于災(zāi)難時(shí)刻保護(hù)通訊網(wǎng)絡(luò)的地下走廊。這類走廊對(duì)于在城市地鐵站和中心

18、生產(chǎn)去附近以及市區(qū)外安置地點(diǎn)間運(yùn)送廢棄物和能源也十分有效。這一點(diǎn)不僅緩解了堵塞而且提供了更加有效的能源衍生和廢物循環(huán)。這些概念都是針對(duì)城市建筑的升級(jí)，將最終導(dǎo)致地表形成更開闊的空間以及更高效更吸引人的全局環(huán)境。</p><p>　　當(dāng)展望將來城市建設(shè)時(shí)，地下建筑會(huì)成為主要因素——這是建筑師Paolo Soleri在過去30年的幻想杰作。在科幻小說里，未來城市常被描繪成自我供養(yǎng)的，氣候可控制的單位，且常常位于地下以

19、避免來自危險(xiǎn)或環(huán)境污染等因素的侵襲。在這種情況下，地球上的地下城市略不同于以月球或其他孤立環(huán)境為基礎(chǔ)創(chuàng)建的城市。</p><p><b>　　高層建筑</b></p><p><b>　　前 沿</b></p><p>　　高層建筑的定義很難確定。可以說2-3層的建筑物為底層建筑，而從3-4層地10層或20層的建筑物為中層

20、建筑，高層建筑至少為10層或者更多。</p><p>　　盡管在原理上，高層建筑的豎向和水平構(gòu)件的設(shè)計(jì)同低層及多層建筑的設(shè)計(jì)沒什么區(qū)別，但使豎向構(gòu)件的設(shè)計(jì)成為高層設(shè)計(jì)有兩個(gè)控制性的因素：首先，高層建筑需要較大的柱體、墻體和井筒；更重要的是側(cè)向里所產(chǎn)生的傾覆力矩和剪力變形要大的多，必要謹(jǐn)慎設(shè)計(jì)來保證。</p><p>　　高層建筑的豎向構(gòu)件從上到下逐層對(duì)累積的重力和荷載進(jìn)行傳遞，這就要有較大

21、尺寸的墻體或者柱體來進(jìn)行承載。同時(shí)，這些構(gòu)件還要將風(fēng)荷載及地震荷載等側(cè)向荷載傳給基礎(chǔ)。但是，側(cè)向荷載的分布不同于豎向荷載，它們是非線性的，并且沿著建筑物高度的增加而迅速地增加。例如，在其他條件都相同時(shí)，風(fēng)荷載在建筑物底部引起的傾覆力矩隨建筑物高度近似地成平方規(guī)律變化，而在頂部的側(cè)向位移與其高度的四次方成正比。地震荷載的效應(yīng)更為明顯。</p><p>　　對(duì)于低層和多層建筑物設(shè)計(jì)只需考慮恒荷載和部分動(dòng)荷載時(shí)，建筑物

22、的柱、墻、樓梯或電梯等就自然能承受大部分水平力。所考慮的問題主要是抗剪問題。對(duì)于現(xiàn)代的鋼架系統(tǒng)支撐設(shè)計(jì)，如無特殊承載需要，無需加大柱和梁的尺寸，而通過增加板就可以實(shí)現(xiàn)。</p><p>　　不幸的是，對(duì)于高層建筑首先要解決的不僅僅是抗剪問題，還有抵抗力矩和抵抗變形問題。高層建筑中的柱、梁、墻及板等經(jīng)常需要采用特殊的結(jié)構(gòu)布置和特殊的材料，以抵抗相當(dāng)高的側(cè)向荷載以及變形。</p><p>　　

23、如前所述，在高層建筑中每平方英尺建筑面積結(jié)構(gòu)材料的用量要高于低層建筑。支撐重力荷載的豎向構(gòu)件，如墻、柱及井筒，在沿建筑物整個(gè)高度方向上都應(yīng)予以加強(qiáng)。用于抵抗側(cè)向荷載的材料要求更多。</p><p>　　對(duì)于鋼筋混凝土建筑，雖著建筑物層數(shù)的增加，對(duì)材料的要求也隨著增加。應(yīng)當(dāng)注意的是，因混凝土材料的質(zhì)量增加而帶來的建筑物自重增加，要比鋼結(jié)構(gòu)增加得多，而為抵抗風(fēng)荷載的能力而增加的材料用量卻不是呢么多，因?yàn)榛炷磷陨淼闹?/p>

24、量可以抵抗傾覆力矩。不過不利的一面是混凝土建筑自重的增加，將會(huì)加大抗震設(shè)計(jì)的難度。在地震荷載作用下，頂部質(zhì)量的增加將會(huì)使側(cè)向荷載劇增。</p><p>　　無論對(duì)于混凝土結(jié)構(gòu)設(shè)計(jì)，還是對(duì)于鋼結(jié)構(gòu)設(shè)計(jì)，下面這些基本的原則都有助于在不需要增加太多成本的前提下增強(qiáng)建筑物抵抗側(cè)向荷載的能力。</p><p>　　增加抗彎構(gòu)件的有效寬度。由于當(dāng)其他條件不變時(shí)能夠直接減小扭矩，并以寬度增量的三次冪形式

25、減小變形，因此這一措施非常有效。但是必須保證加寬后的豎向承重構(gòu)件非常有效地連接。</p><p>　　在設(shè)計(jì)構(gòu)件時(shí)，盡可能有效地使其加強(qiáng)相互作用力。例如，可以采用具有有效應(yīng)力狀態(tài)的弦桿和桁架體系；也可在墻的關(guān)鍵位置加置鋼筋；以及最優(yōu)化鋼架的剛度比等措施。</p><p>　　增加最有效的抗彎構(gòu)件的截面。例如，增加較低層柱以及連接大梁的翼緣截面，將可直接減少側(cè)向位移和增加抗彎能力，而不會(huì)加大

26、上層樓面的質(zhì)量，否則，地震問題將更加嚴(yán)重。</p><p>　　通過設(shè)計(jì)使大部分豎向荷載，直接作用于主要的抗彎構(gòu)件。這樣通過預(yù)壓主要的抗傾覆構(gòu)件，可以使建筑物在傾覆拉力的作用下保持穩(wěn)定。</p><p>　　通過合理地放置實(shí)心墻體及在豎向構(gòu)件中使用斜撐構(gòu)件，可以有效地抵抗每層的局部剪力。但僅僅通過豎向構(gòu)件進(jìn)行抗剪是不經(jīng)濟(jì)的，因?yàn)槭怪傲河凶銐虻目箯澞芰?，比用墻或斜撐需要更多材料和施工工作?/p>

27、。</p><p>　　每層應(yīng)加設(shè)充足的水平隔板。這樣就會(huì)使各種抗力構(gòu)件更好地在一起工作，而不是單獨(dú)工作。</p><p>　　在中間轉(zhuǎn)換層通過大型豎向和水平構(gòu)件及重樓板形成大框架，或者采用深梁體系。</p><p>　　應(yīng)當(dāng)注意的是，所有高層建筑的本質(zhì)都是地面支撐的懸臂結(jié)構(gòu)。如何合理地運(yùn)用上面所提到的原則，就可以利用合理地布置墻體、核心筒、框架、筒式結(jié)構(gòu)和其他豎向

28、結(jié)構(gòu)分體系，使建筑物取得足夠的水平承載力和剛度。本文后面將對(duì)這些原理的應(yīng)用做介紹。</p><p><b>　　剪力墻結(jié)構(gòu)</b></p><p>　　在能夠滿足其他功能需求時(shí)，高層建筑中采用剪力墻可以經(jīng)濟(jì)地進(jìn)行高層建筑的抗側(cè)向荷載設(shè)計(jì)。例如，住宅樓需要很多隔墻，如果這些隔墻都設(shè)計(jì)為實(shí)例的，那么他們可以起到剪力墻的作用，既能抵抗側(cè)向荷載，又能承受豎向荷載。對(duì)于20層以

29、上的建筑物，剪力墻極為常見。如果給與足夠的寬度，剪力墻能夠有效地抵抗30-40層甚至更多的側(cè)向荷載。</p><p>　　但是，剪力墻只能抵抗平行于墻平面的荷載（也就是說不能抵抗垂直于墻的荷載）。因此有必要經(jīng)常在兩個(gè)相互垂直的方向設(shè)置剪力墻，或者在盡可能多的方向布置，以用來抵抗各個(gè)方向的側(cè)向荷載。并且，墻體設(shè)計(jì)還應(yīng)考慮扭轉(zhuǎn)的問題。</p><p>　　在設(shè)計(jì)過程中，兩片或者更多的剪力墻會(huì)布

30、置成L型或者槽形。實(shí)際上，四片內(nèi)剪力墻可以被聯(lián)結(jié)成矩形，以更有效地抵抗側(cè)向荷載。如果所有外部剪力墻都連接起來，整個(gè)建筑物就像是一個(gè)筒體，將會(huì)具有很強(qiáng)的抵抗水平荷載和抵抗扭矩的能力。</p><p>　　通常混凝土就剪力墻都是實(shí)體的，并在有要求時(shí)開洞，而鋼筋剪力墻常常是做成桁架式。這些桁架上可能布置成蛋單斜撐、X斜撐及K斜撐。在側(cè)向力作用下這些桁架的組合構(gòu)件受到或拉或壓力。從強(qiáng)度和變形控制角度來說，桁架有著很好的功

31、效，并且管道可以在構(gòu)件之間穿過。當(dāng)然，鋼桁架墻的斜向構(gòu)件在墻體上要正確放置，以免妨礙開窗、循環(huán)以及管道穿墻。</p><p>　　如上所述，電梯強(qiáng)、樓梯間及設(shè)備豎井都可以形成筒狀體，常常用它們既抵抗豎向荷載又抵抗水平荷載。這些筒的橫斷面一般駛矩形或圓形，由于筒結(jié)構(gòu)作用，筒狀結(jié)構(gòu)能夠有效地進(jìn)行各個(gè)方向上的抗彎和抗剪。不過在這樣的結(jié)構(gòu)設(shè)計(jì)中存在的問題是，如何保證在門洞口和其他孔洞的強(qiáng)度。對(duì)于鋼筋混凝土結(jié)構(gòu)，通過使用特

32、殊的鋼筋配置在這些孔洞的周圍。對(duì)于鋼剪力墻，則要求在開洞處加強(qiáng)節(jié)點(diǎn)連接，以抵抗洞口變形。</p><p>　　對(duì)于很多高層建筑，如果墻體和筒架進(jìn)行合理地安排與連接，會(huì)起到很好的抵抗側(cè)向荷載的作用。還要求由這些結(jié)構(gòu)分體系提供的剛度在各個(gè)方向上應(yīng)大體對(duì)稱。</p><p><b>　　框架結(jié)構(gòu)</b></p><p>　　在建筑物結(jié)構(gòu)設(shè)計(jì)中，用于抵

33、抗豎向和水平荷載的框架結(jié)構(gòu)，常作為一個(gè)重要且標(biāo)準(zhǔn)的型式而被采用。它適用于低層、多層建筑物，亦可用于70-100層高的高層建筑物。同剪力墻結(jié)構(gòu)相比，這種結(jié)構(gòu)更適合在建筑物的內(nèi)部或者外圍的墻體上開設(shè)矩形孔洞。同時(shí)它還能充分利用建筑物內(nèi)在任何情況下都要采用的梁和柱的剛度，但當(dāng)柱子與梁剛性連接時(shí)，通過框架受彎來抵抗水平和豎向荷載會(huì)使這些柱子的承載能力變得更大。</p><p>　　大多情況下，框架的剛度不如剪力墻，因此對(duì)

34、于細(xì)長(zhǎng)的建筑物將會(huì)出現(xiàn)過度變形。但正是因?yàn)槠淙嵝?，使得其與剪力墻結(jié)構(gòu)相比具有更大的延性，因而地震荷載下不易發(fā)生事故。例如，如果框架局部出現(xiàn)超應(yīng)力時(shí)，那么其延性就會(huì)允許整個(gè)結(jié)構(gòu)出現(xiàn)倒塌事故。因此，框架結(jié)構(gòu)常被視為最好的高層抗震結(jié)構(gòu)。另一方面，設(shè)計(jì)得好的剪力墻結(jié)構(gòu)也不可能倒塌。</p><p>　　對(duì)于混凝土框架結(jié)構(gòu)，還存在較大的分歧。的確。如果在混凝土框架設(shè)計(jì)時(shí)不進(jìn)行特殊的延性設(shè)計(jì)，那么他將很難承受比設(shè)計(jì)標(biāo)準(zhǔn)值大很

35、多倍的地震荷載的沖擊。因此，很多人認(rèn)為它不具備鋼框架所具備的超載能力。不過最新的研究i和實(shí)驗(yàn)表明，當(dāng)混凝土中放入充分的鋼箍和節(jié)點(diǎn)鋼筋時(shí) ，混凝土框架框架也能表現(xiàn)出很好的延性。新建筑規(guī)范對(duì)所謂延性混凝土框架有專門的規(guī)定。然而，這些規(guī)范往往要求在框架的某處增設(shè)過多的鋼筋，這就增加了施工的難度。盡管這樣，混凝土框架設(shè)計(jì)還是具備既經(jīng)濟(jì)又實(shí)用的特性。</p><p>　　當(dāng)然，還可以在建筑結(jié)構(gòu)設(shè)計(jì)中，將框架結(jié)構(gòu)和剪力墻結(jié)構(gòu)

36、結(jié)合起來使用。例如，在房屋建筑上使用框架，而在另一方向上可以使用剪力墻。</p><p><b>　　結(jié)論</b></p><p>　　以上所述就是高層建筑最普通的結(jié)構(gòu)形式。在設(shè)計(jì)過程中，應(yīng)盡可能經(jīng)濟(jì)實(shí)用地選擇合理的形式。</p><p>　　Underground Space Utilization</p><p>

37、;　　The rapid growth of world civilization will have a significant impact on the way humans live in the future. As the global population increases and more countries demand a higher standard of living, the difficulty of d

38、oing this is compounded by three broad trends: the conversion of agricultural land to development uses; the increasing urbanization of the world`s population; and growing concern for the maintenance and improvement of th

39、e environment, especially regarding global warming and the impa</p><p>　　By moving certain facilities and function underground, surface land in urban areas can be used more effectively , thus freeing space f

40、or agricultural and recreational purpose. Similarly, the use of terraced earth sheltered housing. Using underground space also enables humans to live more comfortably in densely populated areas while improving the qualit

41、y of live.</p><p>　　On an urban or local level, the use of underground facilities is rising to accommodate the complex demands of today`s society while improving the environment . For example, both urban and

42、 rural areas are requiring improved transportation, utility, and recreational services. The state of traffic congestion in many urban areas of the world is at a critical level for the support of basic human living, and i

43、t is difficult if not impossible to add new infrastructure at ground level without causing an</p><p>　　On a national level in countries around the world, global trends are causing the creation and extension

44、of mining developments and oil or gas recovery at greater depths and in more inaccessible or sensitive locations. Three trends have also led to the developments of improved designs for energy generation and storage syste

45、ms as well as national facilities for dealing with hazardous waste (including chemical, biological, and radioactive waste ), and improved high-speed national transportation sys</p><p>　　Land Use Pressures<

46、;/p><p>　　Placing facilities underground is a promising method for helping ease land use pressures caused by the growth and urbanization of the world`s population. Although the average population density in the

47、 world is not large, the distribution of population is very uneven. A map of population density in the world is not large ,areas of the world are essentially uninhabited . These areas are for the most part deserts ,mount

48、ainous regions, or regions of severe cold that do not easily support human habit</p><p>　　If one examines China ,for example ,the average population density is approximately 100 persons per square kilometer,

49、 but the vat majority of the one billion-plus population lives on less than 20 percent of the land area. this is the fertile land that can support food production. However, due to population growth, urbanization, and eco

50、nomic growth, this same land must now support extensive transportation systems, industrial and commercial development, and increasing demands for housing, As the p</p><p>　　The same trend are evident in Japa

51、n, where approximately 80 percent of the land area is mountainous,90 percent of the population lives on the coastal plains, and economic development is concentrated in relatively few economic development is concentrated

52、in relatively few economic centers .The flat-lying land is generally the most fertile and is historically the region of settlement . Other factors adding to population density include the traditional building style , whi

53、ch is low-rise , and Japan</p><p>　　The problem of land use pressures and related economic effects of high land prices are of great interest in the study of the potential uses of underground space. When surf

54、ace space is fully utilized, underground space becomes one of the few development zones available. It offers the possibility of the adding needed facilities without further degrading the surface environment. Without high

55、 land prices, however, the generally higher cost of constructing facilities underground is a significant dete</p><p>　　Planning of Underground Space</p><p>　　Effective planning for underground u

56、tilization should be an essential precursor to the development of major underground facilities. This planning must consider long-term needs while providing a frame work for reforming urban areas into desirable and effect

57、ive environments in which to live and work. If underground development is to provide the most valuable long-term benefit possible , then effective zones beneath public rights-of-way in older cities around the world. The

58、tangled wed of utilizes </p><p>　　The underground has several characteristics that make good planning especially problematical:</p><p>　　Once underground excavations are made, the ground is perm

59、anently altered. Underground structures are not as easily dismantled as surface buildings.</p><p>　　An underground excavation may effectively a large zone of the stability of the excavation.</p><p

60、>　　The underground geologic structure greatly affects the type, size, and costs of facilities that can be constructed, but the knowledge of a region`s can only be inferred from a limited number of site investigation

61、borings and previous records.</p><p>　　Large underground projects may require massive investments with relatively high risks of construction problem, delay, and cost overruns.</p><p>　　Tradition

62、al planning techniques have focused on two-dimensional representations of regions and urban areas . This is generally adequate for surface and aboveground construction but it is not adequate for the complex three-dimensi

63、onal geology and built structures often found underground . Representation of this three-dimensional information in a form that can readily be interpreted for planning and evaluation is very difficult.</p><p&g

64、t;　　In Tokyo, for example, the first subway line (Ginza Line) was installed as a shallow line (10 meters deep) immediately beneath the existing layer of surface utilities. As more subway lines have been added, uncluttere

65、d zones can only be found at the deeper underground levels. The new Keiyo JR line in Tokyo is 40 meter deep. A new underground super highway from Marunouchi to Shinjuku has been proposed at a 50-meter depth. For comparis

66、on, the deepest installations in London are at approximately a 7</p><p>　　Environmental Benefits </p><p>　　Another major trigger for under ground space usage is the growing international concern

67、 over the environment, which has led to attempts to rethink the future of urban and industrial development. The major concerns in balancing economic development versus environmental degradation and world natural resource

68、 limitations revolve around several key issues. These are:</p><p>　　The increasing consumption of energy compared to the limited reserves of fossil fuels available to meet future demand.</p><p>

69、　　The effect on the global climate of burning fossil fuels.</p><p>　　The pollution of the environment from the by-products of industrial development</p><p>　　The safe disposal of hazardous waste

70、s generated by industrial and military activites.</p><p>　　Preserving the environment from the by-products of industrial development economic growth and maintaining individual life styles will be complex if

71、not impossible. However, a high standard of living and high gross domestic product do not have to be proportionately dependent on resource consumption and environmental degradation.</p><p>　　Underground spac

72、e utilization can help solve the environmental/resource dilemma in several ways . Underground facilities are typically energy conserving in their own right. More importantly, by using addition to the obvious benefit of p

73、reserving green space and agricultural land, there is strong evidence that higher urban density can lower fuel resource consumption</p><p>　　The Future of Underground Space Development</p><p>　　

74、Although existing underground facilities throughout the world provide some models for future development, they are all limited in scale, in their lack of a comprehensive vision for the total city environment. As a comple

75、ment to more detailed planning and research studies, it is useful to examine the visions of extensive underground complexes, even entire cities, that have been proposed by futuristic planners and designers.</p>&l

76、t;p>　　Geotech`90, a conference and exhibition held in Tokyo in April 1990, was a major forum for the underground industry in Japan. More than a dozen underground concepts were displayed, ranging from the typical trans

77、it and utility uses to underground corridors that are envisioned as places for a communication network protected during disasters. Such corridors could also effectively transport both waste and energy between substations

78、 in the city and central generation and disposal sites outside the ci</p><p>　　When completely new cities are envisioned for the future, the underground often is a major component, as illustrated by the work

79、 of the architect Paolo Soleri over the last 30 years. In science fiction future cities often are depicted as self-contained, climate-controlled units frequently located underground for protection from the elements and p

80、ossibly from a hazardous or polluted environment. In this case, underground cities on earth differ little from bases created on the moon or other isolat</p><p>　　High-Rise Buildings</p><p>　　I

81、ntroduction</p><p>　　It is difficult to define a high-rise building . One may say that a low-rise building ranges from 1 to 2 stories . A medium-rise building probably ranges between 3 or 4 stories up to 10

82、or 20 stories or more . </p><p>　　Although the basic principles of vertical and horizontal subsystem design remain the same for low- , medium- , or high-rise buildings , when a building gets high the vertica

83、l subsystems become a controlling problem for two reasons . Higher vertical loads will require larger columns , walls , and shafts . But , more significantly , the overturning moment and the shear deflections produced by

84、 lateral forces are much larger and must be carefully provided for .</p><p>　　The vertical subsystems in a high-rise building transmit accumulated gravity load from story to story , thus requiring larger col

85、umn or wall sections to support such loading . In addition these same vertical subsystems must transmit lateral loads , such as wind or seismic loads , to the foundations. However , in contrast to vertical load , lateral

86、 load effects on buildings are not linear and increase rapidly with increase in height . For example under wind load , the overturning moment at the ba</p><p>　　When the structure for a low-or medium-rise bu

87、ilding is designed for dead and live load , it is almost an inherent property that the columns , walls , and stair or elevator shafts can carry most of the horizontal forces . The problem is primarily one of shear resist

88、ance . Moderate addition bracing for rigid frames in“short”buildings can easily be provided by filling certain panels ( or even all panels ) without increasing the sizes of the columns and girders otherwise required for

89、vertical loads</p><p>　　Unfortunately , this is not is for high-rise buildings because the problem is primarily resistance to moment and deflection rather than shear alone . Special structural arrangements w

90、ill often have to be made and additional structural material is always required for the columns , girders , walls , and slabs in order to made a high-rise buildings sufficiently resistant to much higher lateral deformati

91、ons . </p><p>　　As previously mentioned , the quantity of structural material required per square foot of floor of a high-rise buildings is in excess of that required for low-rise buildings . The vertical co

92、mponents carrying the gravity load , such as walls , columns , and shafts , will need to be strengthened over the full height of the buildings . But quantity of material required for resisting lateral forces is even more

93、 significant .</p><p>　　With reinforced concrete , the quantity of material also increases as the number of stories increases . But here it should be noted that the increase in the weight of material added f

94、or gravity load is much more sizable than steel , whereas for wind load the increase for lateral force resistance is not that much more since the weight of a concrete buildings helps to resist overturn . On the other han

95、d , the problem of design for earthquake forces . Additional mass in the upper floors will give r</p><p>　　In the case of either concrete or steel design , there are certain basic principles for providing ad

96、ditional resistance to lateral to lateral forces and deflections in high-rise buildings without too much sacrifire in economy . </p><p>　　Increase the effective width of the moment-resisting subsystems . Thi

97、s is very useful because increasing the width will cut down the overturn force directly and will reduce deflection by the third power of the width increase , other things remaining cinstant . However , this does require

98、that vertical components of the widened subsystem be suitably connected to actually gain this benefit.</p><p>　　Design subsystems such that the components are made to interact in the most efficient manner .

99、For example , use truss systems with chords and diagonals efficiently stressed , place reinforcing for walls at critical locations , and optimize stiffness ratios for rigid frames . </p><p>　　Increase the ma

100、terial in the most effective resisting components . For example , materials added in the lower floors to the flanges of columns and connecting girders will directly decrease the overall deflection and increase the moment